Detail

A SpinButton is an ideal way to allow the user to set the value of some
attribute. Rather than having to directly type a number into a Entry,
SpinButton allows the user to click on one of two arrows to increment or
decrement the displayed value. A value can still be typed in, with the bonus
that it can be checked to ensure it is in a given range.

This is a convenience constructor that allows creation of a numeric
SpinButton without manually creating an adjustment. The value is initially
set to the minimum value and a page increment of 10 * step is the default.
The precision of the spin button is equivalent to the precision of step.

Note that the way in which the precision is derived works best if step
is a power of ten. If the resulting precision is not suitable for your
needs, use spinButtonSetDigits to correct it.

This handler makes it possible to query the current value and to render
something completely different to the screen using entrySetText. The
return value must be False in order to let the default output routine run
after this signal returns.